Not sticking to a consistent bedtime and wake-up schedule has been linked to a heightened risk of a range of health problems. Photo / Getty Images
We all know that getting enough sleep is important for our health. What science is now beginning to reveal is that having a regular sleep pattern may be even more crucial. Not sticking to a consistent bedtime and wake-up schedule has been linked to a heightened risk of a range of health problems.
The latest research comes from Jean-Philippe Chaput of the University of Ottawa. He drew on data from 72,269 people aged 40-79 who were taking part in the UK Biobank study, none of whom had a history of major cardiovascular events. They wore an activity tracker for seven days to record their sleep. Then, for the next eight years, their incidents of cardiovascular death, heart attack, heart failure and stroke were collected from death registries and hospital records.
After accounting for a range of potentially influential lifestyle factors including physical activity levels, fruit and vegetable intake, alcohol consumption and smoking, irregular sleepers were 26% more likely to have a major cardiovascular event than those with a regular sleep-wake cycle. Moderately irregular sleepers were 8% more likely to do so.
Chaput says the ideal is to go to bed and wake at the same time, plus or minus 30 minutes.
“The wake-up part seems to be even more critical than the bedtime,” he explains. “People tend to catch up on sleep by having a lie-in on the weekend, but that might not be a good thing.”
Moderately irregular sleep is considered plus or minus one hour, and more than one hour counts as irregular.
“It’s a pretty narrow window,” concedes Chaput. “There’s not a lot of leeway. But even if you sleep the recommended 7-9 hours a night, if you don’t go to bed and wake up at the same time every day, it could be bad for you in the long term.”
The occasional late night or sleep-in isn’t likely to cause a problem; it is having irregular sleep patterns over a long period that seems to do the damage.
The effect that researchers saw was remarkably linear – the worse the sleep pattern, the higher chance a person had of experiencing a cardiovascular event.
Scientists are still investigating exactly what is going on in the body, but it seems likely it is linked to the brain’s master clock, a group of nerve cells called the suprachiasmatic nucleus, which regulates most circadian rhythms and controls the release of sleep-wake hormones. When we work against this central pacemaker, it affects hormones and puts stress on the metabolic system, leading to poorer health over time.